Hi Peter,
Yep! I’d change the onboard dip switches to both on for the highest 500mA current limit for a battery that large.
I found the table for the DIP switch positions confusing.
I had to measure the continuity to determine the closed position for the switch.
When the DIP switch is on the 1,2 side it is open circuit, when it is on the ONKE side it is closed.
The device comes with the switch on the 1,2 side, 50mA charge current.
Using 0 & 1 in the table does not relate to open circuit or closed circuit. 0 & 1 usually mean GND & VCC.
It would be better for the web page to show a pic of the DIP switch and the position for 50mA. The back of the board is just as confusing.
Secondly I managed to completely drain a LiPO due to poor software design. (my fault)
This charger only reached 2.7V and would not take the LiPo any higher, even after a few hours.
An Adafruit charger work properly, and switched off when the LiPo reached 4.2V.
Probably I have damaged the LiPO and reduced it life, but I accept that.
Thirdly this charger does not switch off when this damaged LiPo reached 4.2V.
The Adafruit one does with the same LiPO.
I looked into the charger chips and don’t have a lot of faith in this Chinese manufactured one.
The Adafruit charger chip I have full faith in and has served me well over a number of years.
If I use a non damaged LiPo and charge when it gets below 3.5V it works fine and the charger turns off at 4.2V.
I was hoping to use this as a main stay charger for my projects, but my experience so far says I should use the Adafruit charger even though it does not have a USB-C connector.
Regards
Jim
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If you are using a Pi Pico reading ADC.3 will return a 16 bit number related to 1/3 of VSYS.
You then calculate the voltage in your program.
ADC.3 is internal and designed for this, so there is no need for external voltage divider.
But …
If you are using a Pi Pico W, ADC.3 (GPIO29) is also the WiFi SPI clock.
In this case you will have to use a voltage divider as shown by @Liam connected to one of the other ADC pins.
Both methods I have used effectively; the device powers itself off if the battery voltage gets too low.
It took some testing over to time to find the correct reading to use; comparing real measurements with the number returned by the ADC as the battery slowly discharged.
I used 10k and 20k divider. Using resistors less than 10k is not effective due to the current drain through the ADC pin. The ADC design in the RP2040 is not as good as other microcontrollers and Raspberry Pi lists the limitations in the datasheet.
Regards
Jim
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Thanks for the feedback Jim, it’s queued up a couple of improvements we can make on the website and our design philosophy in general.
The ONKE markings are actually two separate markings. “ON” for the on-position and “KE” for the manufacturers mark. Though i appreciate at this scale they get pretty crammed together.
In any case, that’s one for the bag of tricks - DIP switches are generally closed in the upper-position.
I’m not sure I agree - where DIP switch options are used it’s pretty common to see a configuration table where 1 defines ON (closed) and 0 defines OFF (open). Though I agree it would be less ambiguous to use “ON” and “OFF” respectively. I’ve captured an improvement for our website to update the table there with “ON/OFF” instead of “1/0”
That’s pretty curious! How did you observe this? Was it the behaviour of the LED or the current draw that led you to this conclusion?
I wish the status line was broken out, like on the DFR0668. I don’t think I need the 3.3V regulator and will probably desolder it. I don’t need 5V either. Just trying to do a LiPo powered NeoTrellis which needs >3.5V and has its own 3.3V regulator. It’s going to be in a box, the board will not be visible. If I had that status line, I’d connect it to a microcontroller I/O and use the NeoTrellis to show charging status.
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Right, when we designed this we only considered visual status for the user.
To make this work with the board as-is you’d have to do some SMT bodging to break out from eg. the status LED resistor’s (R6) pad.
There are lots of chargers out there though! This one was always intended to be very low-fuss, and in this case that meant minimising options and reducing visual complexity.
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Just an update to my previous post.
Now in a project and gone through a couple of charge cycles, this device does what it was designed to do, nicely. It is charging the LiPo I inadvertently drained to 0V and the charger turns off when it should. Don’t know why it didn’t before. Possible the LiPo has recovered somewhat.
The project is a remote control for a RC Cart.
It detects when the LiPo voltage has fallen to 3.5V and flashes a LED.
This is a clear indication it needs a charge.
I like this charger for its easy of use, size, and the USB-C connector.
It is currently used in two of my projects and will be considered for others.
Cheers
Jim
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Hi,
I’m having the same problem as PJ, I have connected the battery board with a 2000mAh battery and to an esp32 mcu however when i measured with a multimeter, I’m getting a voltage between 3.1-3.3 which is good but a current of only 0.5-2 mA max although the board is meant to supply a current of 200mA max. I initially thought that the battery maybe drained but I charged it up and that works through the board I could see it being 100% on the serial monitor when i test it with the battery pin on the board but the output is still 1-2mA.
How do I fix this??
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Hi Jaira
Welcome
First question. Is the ESP32 working OK.
This could be perfectly normal. The 3.3V out is capable of SUPPLYing 200mA Max but the actual current supplied will be what the load (in this case your ESP32) NEEDS. that is if your load only requires 1 - 2mA at any one time that is all that will flow from the supply.
Second question how are you measuring this current. Be aware that if you are using mA ranges on a DMM the meter will have a “voltage burden” which is the actual voltage drop across the meter itself which means that the actual voltage applied to the load will be reduced by this much and could influence the operation of the load. In some cases stopping a device working altogether.
It is possible that this is happening and your ESP32 stops working with the meter connected and the current drain under these conditions is indeed 1 - 2mA. or maybe that is actually the current drain in some sort of “idle” condition.
Cheers Bob
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@Jairaj263534 To test the 3.3V output of the USB-C LiPo Charger board remove the ESP32 and connect a resistor across 3.3V and GND. About 20 ohm 1watt should give a current of 165mA. (3.3/20 = 0.165)
Tested with a 33 ohm 5w (didn’t have a 20 ohm), 91.5mA, 3.276V. (3.276/33 = 99)
Within the margin of error for a wire wound resistor and my old multimeter.
The ESP32 in sleep mode draws very little current.
As @Robert93820 said there are other things to consider when measuring current.
It might be it has shut down because the voltage has dropped too low.
Another consideration is the ESP32 can draw up to 240mA when it is transmitting.
This would overload the voltage regulator causing it to shutdown, the ESP32 then turn off.
Could be why you are seeing low current.
Cheers
Jim
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Oh that would make sense, if wifi transmission takes 240mA then this board won’t be able to support it.
Thanks for the help.
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Hi Jairaj,
Bob and Jim have you off to an amazing start - would it also be possible to send through a photo of how you have everything connected?
Do you have the 3.3V connected directly into the 3.3V input on the ESP32 or the Vin pin?
Keen to get to the bottom of this one!
That is a rough drawing of how everything was connected and the 3v3 was connected to VIN, for now i’ve taken out the battery and attached a micro usb cable and it works fine with that set up.
P.S the resistors are 10.06kOhm each and the wires on the right connect to an e-ink display.
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Hi,
I’ve got one of these chargers and also this battery: Polymer Lithium Ion Battery (LiPo) 3.7V 1100mAh.
I’ve seen the warnings about them exploding etc. and I just wanted to know if my setup is safe and the lipo charger will ensure that the battery doesn’t drain too far and become unsafe?
(My setup is: Lipo battery connected to charger. 3v3 Out connected to Rpi pico Vsys. I will also include @Liam suggestion, with 50k resistor between Battery and Pico ADC and 100k resistor between ADC and GND.)
Thx in advance,
John
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Hi @John123, Welcome to the Forums!!!
Looks mostly good. The biggest thing is the MakersVerse Board doesn’t have any discharge protection so it will over drain the LiPo battery. The battery itself does have an over-discharge protection onboard but it is lower than I personally feel comfortable running a LiPo cell at 2.4V.
An alternative that can do the same job and is a bit neater for the Pico is the Pimoroni LiPo SHIM for Pico
It’s Over Discharge protection is a low but reasonable 2.8V and can charge the Lipo through the Pico’s USB connector.
The Makersverse LiPo Charger can still be useful to have around so you can charge the LiPo while the Pico is unpowered.
I hope this helps 
Thx @Aaron.
If I also add in the code to shutoff the pico into deepsleep or similar if the battery voltage falls below, say, 3V, would it be safe?
Hi @John123,
If you are using the 3.3V output from the Makersverse LiPo charger as described in your previous post the Pico will measure 3.3v regardless of battery voltage as it is using a regulated output.
If you used the Battery pin for output to the VSYS on the Pico then your coded shutoff should work.
I’d just make sure it’s properly tested before deploying unmonitored.
Had a friend not realise a UPS board for his Pi didn’t have over-discharge protection for the 18650 cells. He did a battery life test and took the cells down to 2.2v. The over-discharge protection was implemented in the software package for the board when he didn’t realise until I did some digging around.
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I would check when battery voltage falls below 3.5V and use something like the Makerverse Nano Timer to remove power. ie Pico wakes checks battery, if below 3.5V sets pin to active Timer.
I did extensive testing on this in a number of projects. It still means the battery will eventually fall too low if left for too long. Checking at 3.5V allows some over head for the Pico to remain in this state for a number of days, the Nano Timer set for wake every 2 hours.
The Pico ADC is not very good, the measurements can vary quite a lot. When the voltage was close to 3.5V the Pico could become erratic, sometimes starting normally, sometimes not. It lead to incorrect data logging of sensors. The program needed to record when the Pico had detected low voltage once and then not try to start up again.
Also the deepsleep micropython code does not reduce the Pico power consumption enough and can lead to problems in program development. Using a Nano Timer is much more effective.
Regards
Jim
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Received my latest order today which included a Makerverse USB-C Lipo Charger. (CE08374)
The onboard DIP switch is unsoldered on one end allowing the switch to be loose on the motherboard.
This can’t be right?!?
RickW
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